The skin on a person's palms and soles differs from the skin on other parts of a person's body. This skin is covered by rows of narrow ridges. The patterns formed by these ridges appear to be unique to each person. A ridge on a finger can stop, start, and/or bifurcate (i.e., branch). These characteristics are called minutia.
Fingerprint verification is different from fingerprint identification. In a verification system, the claimant claims to be a particular person and the claimant's fingerprint is compared against the fingerprint of the person the claimant claims to be. A determination is then made as to whether or not the claimant is who the claimant claims to be. A fingerprint identification system compares a fingerprint to a number of fingerprints in order to determine if the first fingerprint matches any of the other fingerprints. If a match is made, the first fingerprint is identified as the person to which it matches. Fingerprint verification is less computationally intensive than fingerprint identification and is, therefore, more appropriate for low-cost applications.
Prior art methods of verification using fingerprints appear to fall into one of the following three categories: comparing the entire fingerprint of a claimant to a stored file of an entire fingerprint of the person the claimant claims to be (i.e., an enrollee); extracting characteristic minutia from the fingerprint of the claimant and comparing it to a stored file containing the minutia of the enrollee the claimant claims to be; and comparing the entire fingerprint of the claimant against a stored file of the enrollee the claimant claims to be that contains less than an entire fingerprint of the enrollee.
Comparing a claimant's entire fingerprint against an enrollee's entire fingerprint is not cost effective in low-cost applications (e.g., car-door entry systems, smart-card or PCMCIA card systems, etc.) mostly because of the size and expense of the scanner required to capture an entire fingerprint and partly because of the amount of memory required to store and process the claimant's entire fingerprint.
Extracting characteristic minutia from the claimant is compute intensive and, possibly, memory intensive. Therefore, this approach may also be impractical for low-cost applications for the same reasons as listed above.
Some fingerprint verification systems reduce the amount of information stored, but such systems are only practical in applications where it is acceptable to have a false acceptance error rate higher (i.e., declaring a match when no such match should be declared) than that obtained by a system using an entire fingerprint. A false rejection error is declaring no match when a match should be declared. There is a need for a method of fingerprint verification that may be implemented in a low-cost application that has an acceptable false acceptance error rate.
U.S. Pat. No. 4,015,240, entitled "PATTERN RECOGNITION APPARATUS," discloses a fingerprint verification device that captures an entire fingerprint image by scanning in every section of the entire fingerprint image and storing the various sections in storage registers. The present invention does not capture the entire fingerprint image of the claimant. U.S. Pat. No. 4,015,240 is hereby incorporated by reference into the specification of the present invention.
U.S. Pat. No. 4,581,760, entitled "FINGERPRINT VERIFICATION METHOD," discloses a method of comparing the entire fingerprint of a claimant to a subset of an enrollee's fingerprint in order to determine if the claimant is the enrollee the claimant claims to be. The method of U.S. Pat. No. 4,581,760 reduces the amount of storage required for the enrollees, but it still requires a large input device for capturing the entire fingerprint of the claimant. The present invention does not require the capture of the claimant's entire fingerprint. The present invention offers a cost reduction over the method of U.S. Pat. No. 4,581,760 by not requiring a large input device for capturing an entire fingerprint. The method of U.S. Pat. No. 4,581,760 may also suffer from a higher false acceptance error rate as compared to the present invention. U.S. Pat. No. 4,581,760 is hereby incorporated by reference into the specification of the present invention.
U.S. Pat. No. 4,641,350, entitled "FINGERPRINT IDENTIFICATION SYSTEM," discloses a fingerprint identification device and method that uses a 64.times.64 element window for capturing the fingerprint of an enrollee and a larger 96.times.96 element window for capturing the fingerprint of a claimant. U.S. Pat. No. 4,641,350 stores more information for the claimant then it does for the enrollees. The present invention does just the opposite. The present invention stores the entire fingerprint of an enrollee and captures a smaller subset of the claimant's fingerprint. U.S. Pat. No. 4,641,350 is hereby incorporated by reference into the specification of the present invention.
U.S. Pat. No. 4,805,223, entitled "SKIN-PATTERN RECOGNITION METHOD AND DEVICE," also discloses a method of comparing the entire fingerprint of a claimant to a subset of each enrollee's fingerprint in order to attempt to identify the claimant as an enrollee. U.S. Pat. No. 4,805,223 also discloses an alternate embodiment that compares a sparsely sampled entire fingerprint of the claimant to the entire fingerprint of an enrollee. Both embodiments of U.S. Pat. No. 4,805,223 require an input device for capturing the claimant's entire fingerprint. The present invention does not require the capture of the claimant's entire fingerprint. U.S. Pat. No. 4,805,223 is hereby incorporated by reference into the specification of the present invention.
U.S. Pat. No. 5,067,162, entitled "METHOD AND APPARATUS FOR VERIFYING IDENTITY USING IMAGE CORRELATION," and U.S. Pat. No. 5,144,680, entitled "INDIVIDUAL IDENTIFICATION RECOGNITION SYSTEM," each disclose a method of comparing characteristic minutia from the entire fingerprint of a claimant to characteristic minutia from the entire fingerprint of one or more enrollees in order to attempt to identify the claimant as an enrollee. The methods of U.S. Pat. Nos. 5,067,162 and 5,144,680 each require an input device for capturing the entire fingerprint of the claimant. The present invention does not require the capture of a claimant's entire fingerprint. U.S. Pat. Nos. 5,067,162 and 5,144,680 are hereby incorporated by reference into the specification of the present invention.
U.S. Pat. No. 5,239,590, entitled "FINGERPRINT VERIFICATION METHOD," discloses a method of comparing the fingerprint of a claimant to the fingerprint of an enrollee the claimant claims to be in order to attempt to determine whether or not the claimant is the enrollee. U.S. Pat. No. 5,239,590 attempts to reduce the amount of data required to be stored for the enrollees and the claimant by obtaining fingerprint information from the center of characteristic minutia to the tip of the finger. Not knowing before hand where the center of characteristic minutia is, the method of U.S. Pat. No. 5,239,590 still requires the capture of a substantial portion of the claimants fingerprint in order to determine where the center of the characteristic minutia is. The present invention does not require the capture of a substantial portion of the claimant's fingerprint. U.S. Pat. No. 5,239,590 is hereby incorporated by reference into the specification of the present invention.
U.S. Pat. No. 5,261,008, entitled "FINGERPRINT VERIFICATION METHOD," and U.S. Pat. No. 5,267,324, entitled "IMAGE COMPARISON METHOD," both disclose a method of fingerprint verification by capturing an entire fingerprint for both enrollees and claimant, but then dividing these images into smaller sections and comparing the corresponding sections. The present invention does not capture the entire fingerprint image of a claimant. U.S. Pat. Nos. 5,261,008 and 5,267,324 are hereby incorporated by reference into the specification of the present invention.
U.S. Pat. No. 5,363,453, entitled "NON-MINUTIAE AUTOMATIC FINGERPRINT IDENTIFICATION SYSTEM AND METHODS," discloses a method of fingerprint identification that captures an entire fingerprint but then reduces the fingerprint image to an area based on ridge count. The present invention does not capture the entire fingerprint image of a claimant. U.S. Pat. No. 5,363,453 is hereby incorporated by reference into the specification of the present invention.